Stretch marks, or striae disease, are the disfiguring permanent scars left in skin usually caused by excessive stretching such as during and after rapid weight gain or pregnancy. These marks occur in 50-90% of all pregnant women, and usually appear in the later half of pregnancy as bright red or purplish lines. While the majority will be on the lower abdomen they can also be found on the thighs, hips, buttocks, breasts and arms of women. During the postpartum period, the reddish lines typically turn into shallow silver scars.
Hydration of the skin via lotions and creams may help reduce the creation of stretch marks and their effects in some cases, but cannot prevent them in women prone to the condition. Studies investigated the effect of applying 0.1 percent tretinoin (retinoic acid or Retin-A) cream to stretch marks (S Kang et al. Topical tretinoin (retinoic acid) improves early stretch marks. Arch Dermatol 1996, 132:519-526.). Both the length and width of the marks were diminished but side effects include dry and itchy skin and moderate to severe erythema. This treatment works best when applied during the first few days postpartum; however, its effects on breastfeeding are not known. It is toxic and teratogenic, and should never be used during pregnancy.
Postpartum light treatment may be helpful to diminish the appearance of stretch marks. For temporary cosmetic relief, ultraviolet light (UVA) exposure may be used to tan the lighter skin areas represented by stretch marks. In the limited cases where stretch marks are darker than the surrounding skin, intense pulsed light may be used to remove pigment. Pulsed dye lasers are also used.
Patterns of thermal ablation to epidermis and/or dermis and/or fibrous fascia are effective for treatment of various skin conditions. Recently, “fractional photothermolysis” using mid-infrared lasers to produce a microscopic array of thermal injury zones that include both epidermis and dermis was reported to be effective and well-tolerated for treatment of skin remodeling. A primary advantage of fractional photothermolysis is that each zone of thermal injury is smaller than can be easily seen with the unaided eye, and surrounded by a zone of healthy tissue that initiates a rapid healing response. Repeat treatments, which are well tolerated, can be performed until a desired result is obtained. However, similar to any light based treatment, fractional photothermolysis poses the disadvantage that it is intrinsically limited to regions of approximately the upper 1 millimeter of skin, because light that propagates more than about 1 mm through skin has been multiply scattered, and can no longer be focused or delivered effectively to the treatment area. Stretch marks involve both superficial and deep layers of the dermis, as well as fibrous fascia. Therefore it is imperative to treat not only near the surface of skin, but all the way down to the deep dermis and fibrous fascia.